A. Field of the Invention
The present invention relates to the field of anatomical teaching apparatus. More particularly, it relates to a cardiac surgical trainer including a heart model and means for animating the model for mimicking the heart for practicing medical procedures in a realistic but simulated manner.
B. Description of the Prior Art
Cardiovascular disease is the leading cause of death in the United States, Europe and Japan claiming more lives each year than all other diseases combined. The prevalence of this disease has resulted in the performance of numerous cardiac related medical procedures. In fact, the number of cardiac procedures including cardiac catheterization, open heart surgery, coronary artery bypass surgery, heart transplants and coronary angioplasty has steadily risen for the past ten years. While these procedures are having a beneficial effect on the medical condition of cardiac patients in general, the success of any particular cardiac procedure is linked to the training and experience of the doctors performing the operation.
Currently, the best method for a cardiac surgeon to obtain experience in performing medical procedures on the human heart, such as cardiac bypass operations, is by actually performing a procedure on a live patient under supervision of an experienced surgeon. However, for obvious reasons this is not the most desirable method for teaching surgical techniques to new surgeons. The use of a cadaver offers an alternative this training method because provides the opportunity to work on a real heart. However this approach also has many disadvantages. Working on a cadaver is unrealistic because the heart tissues are not identical to the tissues of live heart and the movement associated with contractions of the myocardium is obviously missing. Additionally, cadavers are expensive and are generally in short supply. Moreover, a cadaver can be used only for a very limited number of procedures. Finally, the handling of cadavers are often regulated by governmental agencies.
Other technological alternatives for training on real bodies were suggested but they are all deficient in that they do not adequately simulate the look, feel movement of real heart, and its tissues. For example, the patent to Yong, U.S. Pat. No. 6,234,804, teaches a model thorax with an internal cavity enclosing a replica of a heart. While the heart device is equipped to simulate bleeding or blood flow and pressurized circulation through the heart, there is no mechanism for simulating the contractions of the myocardial layer of the heart. Thus, the device does not provide a realistic tool for medical procedures intended to be performed on a beating heart. Prom, U.S. Pat. No. 6,062,866, Younker, U.S. Pat. No. 5,951,301, and Montgomery, U.S. Pat. No. 5,634,797, describe other cardiac models, however they are similarly deficient in that they fail to provide a model capable of simulating myocardial motion.
The Izzat, U.S. Pat. No. 5,947,744 discloses a device which attempts to provide xe2x80x9cbeating-heartxe2x80x9d training. However, the device""s crude implementation of a platform using a cam and variable speed motor are not appropriate for incorporation in an anatomically correct three-dimensional cardiac model made of soft tissue-like material. Moreover, the methods of pumping fluid in and out of a single chamber in a model heart or by a cam striking the surface are insufficient to provide for realistic simulation of complex myocardial motion.
In view of prior art deficiencies, the principal objective of the present invention is to design a cardiac trainer including an anatomically correct heart model that can be used for the training, testing or educational instruction of physicians.
It is a further objective to provide an anatomically correct heart model that is capable of movement that simulates realistically the movement of a heart.
It is a still further objective to provide for an efficient and economical method for manufacturing an accurate and realistic heart model.
Additional objectives will be apparent from the description of the invention as contained herein.
Briefly, a cardiac surgical trainer constructed in accordance with this invention includes a heart model consisting of two portions: an inner cast simulating the myocardium and an outer shell corresponding to the epicardium. Both portions are made of a flexible material such as silicone rubber and are painted to look as close as possible to a human heart, using for example, silicone based paints.
The heart model is made using a two stage process. In a first stage sculptures are made corresponding to the inner and outer surfaces of the myocardium. The sculptures are used to make molds for the inner cast. Next, a separate mold is made corresponding to the whole heart and the inner cast is introduced into the separate mold to allow the shell to be molded thereon.
Preferably, the model is animated so through an animation network and a control device. The animation network consists of tubes imbedded in the heart model and coiled around orthogonal axes. The control device changes the pressure within the tubes in a controlled manner so as to impart to the heart model a multi-dimensional rotational motion similar to a beating heart. In one embodiment, the tubes are made so that they contract longitudinally when they expand radially.
In one embodiment, the heart may then be incorporated into a model thorax with a pericardial well to hold the model heart, which is accessible through a sternotomy opening. The thorax may also be made with anatomically correct ribs, intercostal spaces and artificial skin to yield a life-like operating center. The thorax may be sized to fit within a suitcase type holder for portability.
With this device, surgeons, surgical students and other medical professionals may be trained in procedures and the use of medical devices for off-pump non-arrested heart surgery. By way of example, possible training applications include full open heart procedures, endoscopic procedure, robotic procedures, heart bypass, heart stabilization, left anterior mammary artery (LIMA) and right anterior mammary artery (RIMA) dissection, pericardial suturing, endoscopic port selection and placement. The device may be used to teach other cardiac procedures or to develop new procedures.